Pallet loading apparatus

ABSTRACT

An apparatus for loading objects on a pallet has a cross frame movable vertically between upright supports. There is a shuttle table over the cross frame movably carried on it for travel from a load-receiving position at one end of the frame to a loaddischarge position at the other end with means for traversing it back and forth. A restraining bar movable from a position where it is clear of the load when the table moves forward to a position over the pallet, but which obstructs the load as the shuttle table moves back, causes the load to be forced off the table onto the pallet or partially-formed load already on the pallet. One layer is deposited on the load with each forward and back cycle of the shuttle table. When the load is complete the cross frame is raised to a level above the load to clear the loaded pallet which is then removed, but at all other times the cross frame surrounds the load at or near its top to guard against accidental toppling of the load. An improved restraining bar is on dead center when it is in loadrestraining position with the pivotal axis about which it moves between load-restraining and load-clearing position so that the back thrust of the load against the bar is not transmitted to the bar-moving mechanism.

United States Patent [191 Alduk [111 3,833,132 [4 1 Sept. 3, 1974'PALLET LOADING APPARATUS [76] Inventor: Frank P. Alduk, 116 GuadalcanalRd., New Castle, Pa. 16105 [22] Filed: Apr. 20, 1972 [21] Appl. N0.:245,842

Related US. Application Data [63] Continuation-in-part of Ser. No.854,930, Sept. 3,

1969, abandoned.

[52] US. Cl. 214/6 G, 214/6 DK [51] Int. Cl. B65g 57/22 [58] Field ofSearch 214/6 DK, 6 H, 6 P, 6 G,

214/6 M, 6 N, 8.5 SS, 8.5 A; 198/35 [56] References Cited UNITED STATESPATENTS 3,206,042 9/1965 Peterson 2l4/8.5 SS

3,294,257 12/1966 Davies et al 214/6 P 3,393,812 7/1968 Mayo et al 214/6G 3,429,469 2/1969 Peterson 214/6 DK 3,696,945 10/1972 Bobolts 214/6 GPrimary Examiner-Robert J. Spar Attorney, Agent, or Firm-Parmelee,Miller, Welsh & Kratz I 57 ABSTRACT An apparatus for loading objects ona pallet has a cross frame movable vertically between upright supports.There is a shuttle table over the cross frame movably carried on it fortravel from a load-receiving position at one end of the frame to aload-discharge position at the other end with means for traversing itback and forth. A restraining bar movable from a position where it isclear of the load when the table moves forward to a position over thepallet, but which obstructs the load as the shuttle table moves back,causes the load to be forced off the table onto the pallet orpartially-formed load already on the pallet. One layer is deposited onthe load with each forward and back cycle of the shuttle table. When theload is complete the cross frame is raised to a level above the load toclear the loaded pallet which is then removed, but at all other timesthe cross frame surrounds the load at or near its top to guard againstaccidental toppling of the load. An improved restraining bar is on deadcenter when it is in loadrestraining position with the pivotal axisabout which it moves between loadrestraining and load-clearing positionso that the back thrust of the load against the bar is not transmittedto the bar-moving mechanism.

20 Claims, 24 Drawing Figures PATENTEB 3E? 974 MU 01 W11 INVENTOR FRANKR ALDUK "M my. AM

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PATENIEU 31974 SHEET '11 0F 11 FIG. 22.

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FIG. 24.

PALLET LOADING APPARATUS This invention is for an apparatus forarranging and placing objects on pallets for transportation or storage,and this application is a continuation-in-part of my application Ser.No. 854,930 filed on Sept 3, 1969, now abandoned.

BACKGROUND OF THE INVENTION The stacking of various packages, cases,cartons, blocks and divers other objects on pallets for handling,storage and shipment is now extensively practiced, but in most instancesthe articles must be loaded onto the pallets and put in place, one at atime. Starting with a pallet at ground level, labor receives thearticles from a conveyor or in some other manner where they are liftedindividually and placed on the pallet in a prearranged pattern. At firstthe laborer must bend over to place the first one or two layers, but asthe load builds up, he must lift the articles higher and higher, oftento levels above his shoulders. In many cases the objects are heavy, suchas cases of canned products, paint or solid articles such as buildingblocks, and in any event the work is tiring and may cause physicalinjury.

Attempts have been made to lighten this work, as by having an elevatedwork floor or platform with a pallet support that is lowered as the loadon the pallet builds up, with the loaded pallet being removed at a lowerfloor, but this has many drawbacks, not the least of which is the factthat it is not feasible to provide the required ceiling height, orbecause of other limiting conditions in many plants, while anotherdifficulty arises from the fact that the pallet supporting and loweringdevice must be heavy enough to accept the increasingly heavy load untilthe full load is placed on the pallet. There are other objections whichneed not be here explained. British patent 964,411 cited as a referenceagainst the parent application of which this is a continuation-in-partdiscloses an apparatus designed to perform much the same function asthat of the present invention but has certain drawbacks which willbecome more apparent as the description of my invention proceeds.

SUMMARY OF THE PRESENT INVENTION The present invention provides a uniquepallet loading structure comprising essentially a base having apalletreceiving roller table thereon almost at floor level onto which apallet may be placed, and from which the loaded pallet may be easilypushed to a position where the loaded pallet may be engaged by a forklift truck, or otherwise removed.

This base provides a support for an upright frame comprised of twospaced parallel structural columns, one at each side of the base. Theyare joined by a cross structure at the top. These columns provide aguideway for a verticallymovable horizontal cross frame comprisedprincipally of two spaced horizontal beams carried on trolleys that rideon the uprights, and these beams are attached to the trolleys aboutmidway between their ends so they extend through the upright frame andproject outwardly at each side of the uprights. They are spaced fromeach other a distance such that they may straddle the pallet on theroller table when the cross frame is at its lowest position, andstraddle the load on the pallet as it is progressively built up, neverleaving a position where they support the load against being toppledafter the first few layers have been put in position until the load iscompleted. These beams extend a distance such that their ends are beyondthe most remote edge ofthe pallet at one side of the upright frame. Thebeams at the other side of the frame extend outwardly beyond the uprightframe about the same, or a slightly greater distance. A motordrivenmechanism raises or lowers the cross frame from a convenient home orstarting level under the control of an operator.

Above the cross frame and supported on it for back and forth travel is ashuttle table that is moved between a retracted position at one side ofthe vertical frame to an extended position at the other side of thevertical frame where it is then positioned over the palletreceivingroller table on the base below it. With the shuttle table in theretracted position and the cross frame at the home or loading level, theoperator places the objects in a layer of the desired pattern on theshuttle table which is accessible on three sides for receiving andarranging the load. The cross frame is then lowered or raised, dependingon the extent to which the pallet has been loaded, to a level just abovethe level at which the objects are to be laid, and then the shuttletableis moved back while a restraining bar, forming part of the crossframe assembly, moves into position behind the layer of objects to keepthem from riding back with the shuttle table, so that the objects droponto the pallet, or the previously-formed load on the pallet, as theshuttle table moves back.

Since the cross frame always returns to its home position for loading,this position is arranged to be of a convenient height for the operatorin order to avoid a minimum of lifting, stretching, or bending. Theweight of the load on the pallet is always on the fixed roller table,and not on an elevator or movable platform, and provision of an elevatedfloor for loading is unnecessary.

A primary object of the invention is to provide a pallet loadingapparatus of unique construction designed to reduce the manual laborgenerally required for this work, and which ordinarily is useful incommercial buildings without alterations of the building or theconstruction of elevated platforms. A

A further important object is to provide a machine for this purposewhich will adapt itself to various arrangements of floor space indifferent plants where it is used.

A still further object is to provide amachine for loading pallets whichis relatively simple and inexpensive compared with machines heretoforeprovided for this purpose, and which embodies safety features designedto protect the operator and the load against errorin its operation.

These and other objects and advantages are secured by my invention aswill be understood by.those skilled in the art in the light of thefollowing detailed-description thereof in conjunction with theaccompanying drawings showing a present preferred embodiment of theinvention. In the drawings:

FIGS. 1 to 4 are more or less schematic longitudinal sections throughthe machine showing various operating conditions;

FIG. 5 is a side elevation of the apparatus;

FIG. 6 is a top plan view of the apparatus shown in FIG. 5; i

FIG. 7 is a horizontal section in the plane of line VII- VII of FIG.showing the base structure and roller table, other parts of the machinenot being shown;

FIG. 8 is a detail longitudinal section in the plane of line VIIIVIII ofFIG. 7, part of the base structure being broken away and showing apallet in place with a partial load on the roller table;

FIG. 9 is a front elevation of the machine looking from theload-receiving end;

FIG. 10 is a side elevation on a larger scale of one of the columns ofthe vertical frame, the view here shown being the right-hand column asviewed in FIG. 9, the upper part of the column being broken away;

FIG. 11 is a longitudinal vertical section through the machine in theplane of line XIXI of FIG. 6 with the top portion of the vertical framebeing omitted;

FIG. 12 is a transverse vertical section in the plane of line XII-XII ofFIG. 11;

FIG. 13 is a horizontal section in approximately the plane of lineXIII-XIII of FIG. 9, but on a larger scale, and showing the shuttletable retracted with the previously-established load on the pallet, andshowing electric eye controls;

FIG. 14 is a fragmentary section in the plane of line XIVXIV of FIG. 12;

FIG. 15 is a detail front elevation of one of the guide roller mountingsshown in FIG. 14;

' FIG. 16 is a simplified basic control circuit diagram;

FIG. 17 is a fragmentary side elevation of the inside face of one of theside plates of the vertically movable frame showing a modifiedrestraining bar arrangement with the bar in its uppermost position, theview actually being a section along the center-line of the apparatus;

FIG. 18 is a similar view with the restraining bar in operativeposition;

FIGS. 19 and 20 are fragmentary enlarged detail views of the hinged sidearms on which the restraining bar is carried, FIG. 19 being a top viewand FIG. 20 a side view;

FIG. 21 is a transverse section through one of the upright columns 26,with a modified control arrangement fixed thereto;

FIG. 22 is a side elevation of the column of FIG. 1

with the attached parts, showing one of the side frame members 40 toindicate the cross frame and shuttle;

I FIG. 23 is a fragmentary view at right angles to FIG. 22; and

FIG. 24 is a block type circuit diagram of a portion of the circuit towhich the parts shown in FIGS. 21 to 23 relate.

The invention may perhaps be best understood by a general description ofthe basic parts of the machine and brief reference to the operationfollowed by a more detailed description of the several parts. To thisend, reference will first be made to FIGS. 1 to 4, wherein 2 designatesgenerally a structural base frame to which is secured a fixed uprightframe designated generally as 3. A roller table 4 is set in the baseframe at one side of the upright frame. There is a vertically movablehorizontal cross frame, designated generally as 5, and it is mounted forvertical movement in the upright frame. It extends through the uprightframe with one end extending to the left (as here shown) above andbeyond the roller table 4, and the other end extends to the right of theupright frame a slightly greater distance. Movable horizontally aboveand supported on the cross frame is a shuttle table 6. There is arestraining bar and its operating mechanism designated generally at 7mounted in the cross frame movable in an arc from an elevatedload-clearing position shown in FIGS. 1, 2 and 3 to the load-engagingand restraining position in FIG. 4. A pallet P is shown in place on theroller table, and C represents a conveyor or other means on which theobjects, 0, to be loaded, are brought to the loading apparatus at aconvenient height above the floor.

The schematic views 1 to 4 show graphically the general operation. InFIG. 1 the dotted line position shows the normal home or loading levelof the cross frame, at which level the objects are moved without liftingfrom the conveyor C and where they are manually arranged more or lessaccording to pattern on the shuttle table 6. The pallet in FIG. 1 has nopreviouslydeposited load, so, under the control of the operator, thecross frame 5 is dropped to its lowest level where the shuttle table isin a plane just about an inch or so above the top of the pallet.

FIG. 2 is about the same as FIG. 1 but shows in broken lines threelayers of objects already on the pallet, and the cross frame is justabout at the home level. When the load on the'pallet is above the homeor loading level, it is moved upwardly from the home level to depositthe load which is placed on the shuttle table.

' FIG. 3 shows the next operation after the load has been placed on theshuttle table and the cross frame is at the proper level. In thisposition the shuttle table is moved forward or to the left to the limitof its travel, and as previously indicated it would, with the conditionshown in FIG. 1, just clear the top of the pallet by about an inch, andin FIG. 3 it has about the same clearance above the previously-formedlayer on the pallet.

FIG. 4 shows the next operation in which the restraining bar has beenmoved from a raised loadclearing position of FIGS. 1 to 3 to aload-obstructing position behind the load on the shuttle table. Theshuttle table is moving toward the right as seen in this figure, slidingunder the objects which are now restrained from moving with the tableand crowding onto the pallet, or the previously-deposited load on thepallet.

With this brief description, the detail of the construction of thevarious parts may now be followed.

THE BASE FRAME AND UPRIGI-IT FRAME STRUCTURE The base 2, which is bestshown in FIGS. 5, 6, 7 and 8, is generally rectangular in shape and iscomprised of elongated parallel structural side members 10 connected attheir opposite ends by structural cross members 11. Intermediate thelength of the side members, but, as shown in FIG. 7, between the middleof the length of the rectangle and the right end, there is anintermediate cross member 12. This provides an almost square open space13 between the intermediate cross member 12, the left end cross member11, and the two side frame members 10.

The roller table unit 4 set into this square space 13 which comprisesgenerally a rectangular frame having main side bearing bars 15 and endcross bars 16, all rigidly connected together. The two ends of thisframe are here shown as setting on the two side members 10 of the base(see FIG. 7) with the table frame at one end being positioned betweenspaced lugs 17 on one of the base side frame members 10. However, ashereinafter more fully explained, this frame may be turned 90 from thisposition so that the end cross bars rest on the intermediate cross bar12 and the left base end member 11, the frame then being positionedbetween lugs 17a on the intermediate cross member 12.

The table frame structure -16 supports a plurality, preferably three,spaced parallel roller conveyor units 18 of familiar construction, therebeing cross members 19 in the frame 15 and 16 for supporting theseroller conveyor units. In FIG. 8 a pallet P of the usual woodenconstruction is indicated in position on these roller conveyors 18 sothat the pallet is firmly supported in a level position, but it can berolled off the roller table to one side or the other, the pallet movingof course in a direction at right angles to the rollers. However, insome plants the floor arrangement may not accommodate an operation wherethe pallets are moved off one side or the other of the base, and in thiscase, the table is turned 90 to the position shown in FIG. 7, aspreviously explained, and then the conveyors will extend in thedirection of the length of the base, enabling the pallets with theirloads to be moved off the end of the base instead of off one side or theother. If desired, the roller conveyors may be power-driven in a mannernow well known in the art.

There is an advantage of providing a roller table pallet support carriedby, but separate from the base, since it enables one model of a machineto fit into the requirements of the plant where it is used without beingspecially constructed for its environment. While this is a desirablefeature, it will be apparent that any roller table could be provided onthe base in its place. To enter the pallet for the loading operation tobe hereinafter described, there are side guides 20 along each side ofthe roller table. There is also a movable stop bar 21 provided on abracket 22, which stop bar in the horizontal position shown in FIGS. 7and 8 obstructs the free movement of the pallet on the roller table whenthe pallet abuts it, but as indicated by the arrows in FIG. 8, the stopbar may be raised in an arc out of pallet-engaging position.

The upright frame comprises two spaced parallel structural columns 25and 26, preferably of H section with the cross bar of the H parallelwith the base members 10. One of these columns is secured to each of thebase members 10 in line with the intermediate cross member 12 of thebase. Angle braces or gusset plates 27 are provided for securing them totheir respective base structures 10 and keep them perpendicular.

As best seen in FIGS. 5, 6 and 9, the tops of these columns each havestructural plates 28, and there are two structural cross members 29, oneat each side of the columns, secured to these plates for connecting thetops of the columns and keeping them parallel.

The cross bars 29 also provide a support for a reversible motor 30, andreducing gear 31 for driving a cross shaft 32 carried in bearings 33,one of which bearings is at the top of each vertical column 25 and 26.

It' will be noted that the columns 25 and 26, being of H section and setwith the web or cross bar of the H parallel with the length of the base,each provide a channel in their respective confronting faces. There is asprocket wheel 34 on the shaft 32 above each of these channels, and eachchannel has a similar sprocket wheel 34a (see FIGS. 6 and 9) rotatableabout a stub shaft close to the lowermost end of each column (see FIGS.9, l0 and 11). A sprocket chain 35 passes around the top and bottomsprockets 34 and 34a at each side of the machine, with the two verticalreaches of the chain being received in the channels of the respectivecolumns.

The motor, reducing gear, shaft, and sprockets 34 and 34a provide themechanism for raising or lowering the movable cross-frame assembly ofthe machine in the manner to be hereinafter described.

THE CROSS FRAME AND SHUTTLE TABLE ASSEMBLY The vertically-movable crossframe comprises two parallel structural beams 40 of channel section (SeeFIGS. 5, ll, 12 and 13). They extend through the upright frame with oneof the beams being close to the inside face of each upright 3 so thatthe distance between them is slightly greater than the width of a palletand about the same as or slightly less than the length of the rollerconveyor units of the roller table 4. As best seen in FIG. 5, theforward or left ends of the beams extend from the vertical columns adistance beyond the left side of the roller table, and their right orrear ends extend beyond or to the right of the vertical columns an equalor preferably a somewhat greater distance from the uprights, and wellbeyond the right end of the base, so that the base in no way interfereswith an operator who may be loading articles onto the shuttle table. Thebeams 40 are connected at the right or rear ends by a cross channel 41,and there are cross braces 42 (FIG. 11) extending between themintermediate their ends. There may or may not be a cross bar 43 at theirforward or left ends, but there must be an open space between them atthe left or forward end greater than the area of the pallet.

Each of these side beams 40 has a verticallyextending side plate 44secured to the outer face thereof at the location where the beams passthrough the upright frame (see FIGS. 12, 13 and 14), these plates beinginterposed between the vertical columns of the upright frame and thebeams. As best seen in FIG. 12, each sprocket chain has one verticalreach attached to a lug 45 carried on the adjacent side plate near thetop of the plate, and the same reach is attached to a lug 46 near thebottom of the side plate. In fact the two ends of the chain end at theselugs 45 and 46 and the side plate comprises the connecting link betweenthe chain ends. It is through these connections that the cross frame ismoved up and down in the vertical frame when the chain is driven one wayor the other.

To keep the cross frame free of tipping and level at all times, thedrive chains are not only of even efiective length and are driven inisochronism, but the side plates are guided by smooth, free-runningengagement with the vertical columns 25 and 26. As here shown, thisguiding and steadying arrangement is effected by at least three rollerson the outer face of each side plate 44. These rollers 47 are soarranged that the top and bottom ones roll against one of the insideflanges of the vertical column which they confront and the intermediateone rolls against the opposite flange. This staggered arrangement isclearly shown in FIG. 14, so that the cross frame comprises avertically-movable cantilevered truss structure. Each of the flanges ofthe columns 25 and 26 has a vertical bearing strip or track 48 on theinner face of the flange against which the peripheries of these rollersbear (see FIGS. 12 and 13), this track being shown broken away in somefigures for clarity of illustration. In addition to having theirperipheries to hold the platform level, the rollers 47 have shoulders 49that bear against the outer edges of the rails 48 to prevent side swayof the cross frame structure.

To provide necessary adjustment and take up for wear, each roll iscarried on its shaft 50 that passes through a hole 51 eccentricallypositioned in a circular block 52 (See FIG. set in the side plate 44.The outer end of this shaft is threaded and has a retaining nut 53thereon, while the block is clamped in position by keeper-lugs 54 boltedto the side plates, and which extend over a shoulder around the circularblocks. By loosening these lugs and rotating the blocks, the workingcontact of the roller peripheries against the track strips 48 can beestablished and adjusted as required, and by means of the nute 53,endwise adjustment of the roller shafts can be made.

THE SHUTTLE TABLE As best seen in FIG. 12, each side beam 40 has anangle bar 55 secured to its top flange, one leg of the angle bar beingvertical and the other one, resting on the beam 40, being turnedoutwardly. Secured by bolts providing stud shafts therefore are a seriesof spaced rollers 56 along the inner face of the vertical legs of theangle bars 55. The peripheries of these rollers project above the topedges of the angle bars on which they are carried. This series of spacedrollers, like the angle bars 55 on which they are carried, extend alongsubstantially the full lengths of beams 40.

The shuttle table 6 comprises a rectangular rigid metal plate 60, which,as shown in FIG. 12, has its opposite longitudinal marginal edgeportions resting on and supported by the rollers 56 so that the tablemay move freely lengthwise along the cross frame. There are guide strips61 on the under side of the plate that will engage the top edges of therollers to guide the table in its back-and-forth travel along the crossframe. The table preferably has a length greater than half the length ofthe cross frame on which it travels, since, as seen in FIG. 5, itreaches from the vertical columns 25 and 26 to the rear or right end ofthe cross frame when it is in retracted position. There are stop members62 on cross bar 41 at the end of the cross frame at a level where itwill limit the rearward movement of the shuttle table, and there areupright abutments 53 (see FIGS. 5 and 13) at the forward or left ends ofthe angles to limit its travel in the forward direction. The table,which is normally wider than the pallet to be loaded, haslongitudinally-extending side guides 54 secured to the top thereof, eachparallel with, but spaced inwardly from the adjacent side edge of thetable to define the maximum width of the load, which is usually lessthan the width of the pallet, and all objects to be loaded are placed inthe flat area of the shuttle table between these load guides. Asindicated in FIG. 13 these guides may be bolted to the table so thatlimited adjustment of the distance between them for variation in loadwidths may be provided, as indicated at 65.

As best seen in FIG. 12, there is a cross bar 66 suspended by a doublespring suspension with center bolts 67 at each end from the lowerflanges of the beams 40, this bar being located under the shuttle tablenear its forward or left end. It supports bearings 68 for a cross shaft69 near opposite ends of which are friction wheels 70. A reversibleelectric motor and reducing gear assembly 71 at the middle of the crossshaft 69 drives the shaft. The underside of the plate 60 forming theshuttle table 6 rests on these friction wheels, so that when thefriction wheels are driven in one direction or the other, the table isdriven forward or backward, as required. The drive, however, is afriction drive, and the shuttle table is kept on the friction wheels andthe rollers 56 only by its own weight. The spring suspension elements 67are adjusted to provide the desired frictional contact of the wheels 70,which have suitable friction tires, with the table.

As hereinafter more fully pointed out, this friction drive arrangementis an important safety factor and the fact that it is positionedentirely under the shuttle table gives operators full freedom of accessto the table for arranging the successive layers of objects where onelayer will break joints with the one beneath.

THE RESTRAINING BAR ARRANGEMENT A cross bar 75 extends between the upperportions of the side plates 44 of the cross frame (FIG. 12). Dependingfrom it are two spaced arms 76. There is a shaft 77 extending crosswiseof the machine between these two arms with its ends supported in thelower ends of the arms. Around this shaft there is a sleeve 78 havingtwo parallel levers 79 attached thereto near its opposite ends. Therestraining bar 80 itself, is secured to the lower ends of these levers,and it is long enough to extend most of the distance between the loadguides 64 on the table when this bar is in its lower loadrestrainingposition shown in FIG. 12.

The sleeve 78 also has a pair of closely-spaced lever arms 81 extendingtherefrom at an angle to the levers 79 and located near the center ofthe sleeve. A piston rod 82 forming a part of a fluid pressure cylinderand piston unit 83 extends between the arms 81 and is pivotallyconnected thereto. As best seen in FIG. 11, there is a frame structurebolted to the underside of the center of the cross bar comprising rigidparallel structural bars 84 with-upturned ends 85, the tops of which arejoined by cross piece 86. This structure provides a bracket with thecylinder-piston unit 83 positioned between its two side parts 84-85, andwith the upper end of the cylinder pivotally anchored at 87 to a lug 88on the underside of cross piece 86.

With this arrangement, when the piston rod 82 is fully extended by theadmission of fluid pressure to the upper end of the cylinder, therestraining bar is in the elevated position well above the shuttletable, as shown in full lines in FIG. 11, but when fluid pressure isadmitted to the lower end of the cylinder, retracting the piston rod,the sleeve 78 is rotated to swing the restraining bar down through anarc of about 90 or preferably perhaps a little past 90 to the dottedline position shown in FIG. 11.

Since the cross frame is moved=up and down, air pressure for operationof the cylinder-piston unit 83 is supplied from a connection 90 on thebase through a flexible hose 91 to a connection box 92 secured to one ofthe beams 40. A tube 93 leads from this box to a. switch valve 94(FIG.11) where this valve is closed by a contact shoe 95 on the underside ofthe rear of the table. In this position pressure air flows through thevalve and along tube 96, which, as shown in FIG. 12, leads to the topend of cylinder 83. At this time a second switch valve 97 will vent thelower end of the cylinder to atmosphere. When the table has moved allthe way forward, the shoe 95 will operate switch 97 to vent the upperend of the cylinder 83 and supply pressure through line 98 to the lowerend of cylinder 83 to retract the piston in said cylinder and swing therestraining bar down. It will then stay down until the shuttle table hasretracted and the shoe 95 operates valve 94 to vent the lower end of thecylinder and restore pressure to the upper end.

Pneumatic valve circuits of this type are well known in the art and formno part per se of the present invention. The two valves 94 and 97 are sointerconnected that when one is admitting fluid pressure to thecylinder, the other vents the opposite end of the cylinder, but atintermediate times the pressure is held in the end of the cylinder towhich pressure was last applied.

In most cases, one plant or one apparatus will be employed for onestandard load of objects, so there is provided an indicator to show theoperator the levels at which loads are to be placed. It comprises aremovable panel 100 on the upright column 25. This is shown in FIG.where the panel has a key slot 101 near its lower end that engages astud on the face of the column that is turned toward the loading end.There is a similar key slot and pin at 102 at the top of the panel (FIG.9). The panel has markings 103 thereon, preferably comprised of stripsof colored tape with a pressure-sensitive adhesive to removably holdthem on the panel to indicate the levels at which loads are to be placedon the pallet. An indicating pointer 104 on the adjacent crossframe sideplate 44 will indicate the level to which the cross frame is to bemoved. When the character of the I load is changed, the panel may beremoved, the tape markers relocated, and the panel replaced.

Power for the reversible motor 71 on the cross frame is supplied througha flexible cable 105 leading from an outlet box on the base to aconnecting box 106 on the underside of the cross-frame.

All of the elements to carry out the operations outlined in FIGS. 1 to 4have been described. It is only necessary to provide switches to operatethe reversible motor 30 to bring the cross-frame with its shuttle tableto the right or home level for loading, then, after the load is placedon the table, again operate the motor 30 to raise or lower the crossframe to the level just above the level of the surface on which the nextlayer of objects is to be placed on the pallet. After the cross framehas been so raised or lowered, the reversible motor drive 71 is thenoperated to drive the friction wheels in a direction to move the shuttletable to the left as far as it will go against stops 63, and thefriction drive can drive it no further. The restraining bar will lowerat this time and the motor 71 is reversed to bring the table back to itsstarting position, stripping the load from the table onto the pallet orthe previous load on the pallet, as the case may be.

While this sequence of operations may all be effected manually throughthe operation of successive switches, it may be so arranged that alloperations will proceed automatically through a full cycle. This has notbeen fully shown, but certain parts of the circuitry is shown.

ELECTRIC CONTROLS There is an electric control box 110 mounted on theoutside of the column 25 at a convenient height above floor level (seeFIGS. 9 and 10). Should it be more convenient, the panel 100, indicators103 and control box 110 could of course be located on the oppositecolumn 26. The control box has several buttons on one side, theuppermost one designated 111 being pushed to connect the apparatus to asource of operating current, being an on button. The next one, 112,below and to the left as viewed in FIG. 10, is to operate motor 71 tomove the shuttle table on the cross-frame from the retracted orload-receiving position to its extended position, and the third button,1 13, is pressed to reverse the shuttle table and return it to theretracted or loadreceiving position. Below the three buttons justdescribed are four others in a vertical row. The uppermost of these,114, is operated to move the cross-frame up. The next lower one, 115,controls the down movement of the cross-frame. The next lower one, 1 16,is an automatic cycle switch, and the lowermost one, 117, is anemergency stop that may be pressed to instantly stop the machine at anypoint in its operation until the start v or on button 111 is againpressed.

As best seen in FIG. 14, the side of one of the columns, in this casecolumn 25, there are three limit or flag switches close together, thecenter one of which,

designated 120, is at the home or loading level of the cross-frame. Theone immediately above, 121, is an up switch that functions on automaticcycle of the machine to cause continued upward travel when button 116 ispressed after initial pressing of up button 114. The lowermost one, 122,continues the downward travel on automatic cycle when the button 116 ispressed following operation of the down button 115. These switches 120,121 and 122 are operated by an actuator or contactor 123 projecting fromthe side face of the confronting cross-frame side plate 44. In additionthere is a lower limit switch 124 spaced below switch 122 which will beoperated when the crossframe has been lowered to the lowest point of itstravel, which is a level at which the shuttle table 60 will just clearthe top of a pallet on the roller table.

There is a limit switch 125 adjustably positioned on the column 25 at apredetermined level above the home position corresponding to the maximumheight to which the load on the pallet is to be raised (see FIG. 9).

Referring particularly to FIG. 1 1, there is a cable 126 extending fromthe electric outlet box 106 on the crossframe to a limit switch 127adjacent the pneumatic switch 94 arranged to be operated by the shoe 95to stop the motor 71 when the shuttle table is fully retracted and set areverse switch which will cause it to drive the table forward when thecircuit to the motor is next energized. A cable 128 leads from outlet orjunction box 106 to the motor. Another cable, 129, leads from thejunction box to a limit switch 130 located adjacent the pneumatic switch97 for operation by the shoe 95 when the shuttle table is fully extendedfor stopping the drive motor 71 and reversing the circuit when the motoris next energized. These switches and this circuitry is a known type ofcircuit in other environments.

In addition there is included in the motor circuit, not as an essentialelement, but as an added safety feature, a pair of switches 131 and131a, one of which, 131, is at the forward end of the shuttle table andwill operate to stop motor 71 if the shuttle table should move forwardat a level where it strikes the previously-deposited load, and the otherone, 131a, is on the underside of the shuttle table to de-energize bothmotors if the crossframe and shuttle table are moved down against theload before the shuttle table has retracted.

Also there are shown two electric eye circuit control units carried onthe cross-frame at the forward end over the roller table area (see FIG.13). One of these comprises a light projector 135 that projects a lightdiagonally to a photo-sensitive receiver 135a. The arrow between theseelements in FIG. 13 represents the light beam. This circuit is brokenwhen the light beam is interrupted and controls the motor 71 so that itwill not operate if there is an obstruction to the light beam at anylevel. Consequently the cross-frame must be at a level above thepreviously-deposited load on the pallet before the shuttle table drivecan operate to propel the shuttle table forward. It is, however,slightly below the bottom of the shuttle table, so that as the shuttletable moves forward, it does not break the light path.

The other electric eye unit comprises a light projector 136 andphoto-sensitive receiver 136a. This is arranged on the opposite diagonalto the first, the arrow extending between them representing the otherlight beam. The circuit for this unit is closed when the light beam isbroken, and open when the light beam is not interrupted. It controls thecross-frame raising and lowering motor 30 so that the cross-frame willraise the cross-frame only so long as there is a load between thecross-beams so that it will raise above any load and stop when the lightbeam is completed, indicating that the cross-frame is at a level wherethe shuttle table is clear of the load and needs to be lifted no higher.

OPERATION In operating the machine, the cross frame will always at thestart he at the home or loading level. Since the pallet will be empty,the operator knows that the cross frame must go down from the homeposition until the load on the pallet is at or above the home level.Assuming that the operator is loading parallelipiped objects, such ascartons or cases, he will have been provided with a loading pattern soas to break joints in successive layers or courses on the pallet. Hewill arrange the first layer on the shuttle table according to patternbetween the side guides 64 back of the forward edge of the table,preferably roughly in back of the plane of the raised position of therestraining bar 80. In the direction of the length of the table, it doesnot matter if the articles are not closely spaced when initially put inplace because they will be shoved and crowded together when the shuttletable pulls back and the restraining bar holds the load.

The operator, after arranging the first layer, and knowing that thecross-frame must go down, and assuming the on button 111 to have alreadybeen pushed, now pushes the down button 115. Under manual control heholds this button in until the crossframe reaches its lowermostposition. Limit switch 122 prevents the cross-frame from moving too low.He may then push button 112 to drive the shuttle table forward, and atthis level it will be a slight distance, an inch or so above the levelof the pallet. When the shuttle table has been moved to its full limitforward, or to the left end of the cross-frame as here illustrated, theair valve 97 will be operated by shoe95 to swing the restraining bardown to the dotted line position, as described. At about the same timeswitch 130 will open the circuit to the table-driving motor 71. Then theoperator will push button 113 to retract the table to deposit the loadon the pallet. The distance between the restraining bar and the forwardedge of the shuttle table in the extended position is such that for astandard pallet and layer of objects, the table will draw back a fewinches and the first objects will be dropped by the withdrawing tablejust at the left-hand edge of the pallet, since the load is usuallyflush with the edges of the pallet. When the shuttle table has fullyretracted, the switch 127 will operate to stop the motor 71, andpneumatic valve 94 will raise the restraining bar. The operator may thenpush the up or down button as may be required to bring the cross-framedown to the home or loading level at which level limit switch willoperate to stop motor 30. This motor is of the self-braking or automatictype so that there is no overtravel when it is de-energized, and motor71 is also preferably of the self-braking construction, such motorsbeing well known in hoisting apparatus. After one layer of objects hasbeen loaded onto the pallet and the cross-frame has been returned toloading level, the operator arranges another load on the shuttle tableand the operation is repeated until such time as the load level becomeshigher than the home or loading level. When this load height is reachedthe operator pushes the up button first. 1 3

After the last layer of articles has been placed on the now fully loadedpallet, the cross-frame with the shuttle table will be raised clear ofthe load, after which the stop 21 (FIG. 8) will be raised clear of thepallet to enable it to be rolled off the roller table. Should there beno switch 131 on the shuttle table, or should it not operate, andthrough some error the shuttle table would move forward and strike theload, the cross bar 43 would prevent displacement of the load, since itwould always be opposite and slightly below the plane of the shuttletable. After the shuttle table hits the load and loses its inertia, thefriction drive for the table will slip and no damage to the load willoccur.

CONTROL CIRCUIT DIAGRAM Theessential elements of a circuit to effectoperation are disclosed in the diagram (FIG. 16). Automation of thesecontrols to carry out a complete cycle after a start" button has beenpushed is simply a matter of adapting relays and electric eye circuitsto open and close the switches of this diagram, or relays in parallelwith them.

In FIG. 16 the motors 30 and 71 are connected across power supply linesL1 and L2. These motors are controlled through reversing relay switches30a and 71a, respectively. The control circuits are energized by astep-down transformer T having its primary connected across lines L1 andL2. The secondary has one side connected to a common return, indicatedby the ground symbol and the other side to the line 164, through relayoperated emergency of switch 117a which is normally closed, but which isopened by operating push button switch 117 on the control panel. From117a the connection to line 164 includes the manually-operated on switch111 that energizes the entire control circuit. This switch will remainclosed until pushed again to open the circuit. One terminal of each ofthe reversing relays 30a and 71a is connected as indicated by the groundsymbol to the common return. Line 164 leads to flag switch 116 at thehome or loading level. For simplicity this switch is here shown as-onewhich is biased by springs to return to a neutral middle position afterthe flag has been moved up or stud there is a bell-crank 249 that ispivotally supported on the stud. It has a long arm 250 and a short arm251.

There is a fluid pressure cylinder and piston unit 252 pivotallysupported at 253 on a second mounting block 254. The block 254 is boltedto the plate 44, and there are two parallel rows of holes 255 so thatthe block 254 may be adjustably secured in position according to theposition of the mounting block 248.

At the outer end of the long arm 250 of the bellcrank there is anextension 256 that is pivoted at 257 to the end of the long arm. Asshown in FIGS. 19 and 20 the arm 250 and the extension 256 haveoverlapping halfthickness portions 250a and 256a, respectively, throughwhich the pivot pin 257 passes. Extension 256 is beveled at 256b tolimit the free swing which the extension has on pivot 257 relative tothe long arm 250. The joint is a knee-joint which does not permit theextension 256 to swing past an aligned position with respect to the longarm in an upward direction and can drop only through a limited are lessthan 90 downward from a straight line position. The arm 250 with theextension 256 is in effect a toggle lever which increases slightly inlength as the arm 250 swings down to a horizontal position parallel withthe top of the shuttle table. When the arm reaches such horizontalposition as shown in FIG. 18, the section or extension 256 rests on asupporting projection or pin 258.

The restraining bar itself is designated 259 and extends over the pathof travel of the shuttle table. When it is lowered to the position shownin FIG. 18 the thrust of the object O resting on the shuttle table whichis retracting against the restraining bar 259 is horizontal and istransmitted horizontally through the composite arm directly against thestuds 248a of the two mounting blocks 248. When the restraining bar isin this position thrust cannot be exerted in a direction where it mayrock the bell-crank on its pivot so that the cylinders 252 requirelittle more than sufficient pressure to raise or lower the compoundlever arms 250-256 and the restraining bar 259. A series of holes 258ain each plate 44 enables the support 258 to be raised or lowered as theblock 248 is raised or lowered.

The restraining bar, which is here shown as being of roundcross-section, may be square or rectangular, depending on the load to beengaged. The arm extension 256 at each side of the machine has a seriesof regularly-spaced holes 260 therealong. The restraining bar 259 can beadjusted toward or away from the pivot 257 at each side of the machineby a bolt that passes through one of the holes in the extension 256 intothe restraining bar at a selected hole 260. The further back therestraining bar is set toward the pivot 257, the greater will be thedelay in pushing the object or objects 0 from the shuttle table movingin the direction Y of the arrow to the retracted position. This isimportant where the load on the pallet is to overhang the pallet or isto be smaller than the pallet.

' Adjustment of the height of the restraining bar is desirable,depending on the character of the load. With taller cartons, forexample, it may be desirable that the restraining bar engage the cartonsat a higher level.

Many times cartons are stacked on pallets with cover flaps that are onlypartially closed, the flaps being angled upwardly at various anglesbetween about and 45 or even more from the horizontal. Using theapparatus herein described on an automatic cycle, one electric eyesystem comprising elements 136 and 136a will effect the stopping of theupward travel of the vertically-movable frame when a light path is clearfrom one element to the other, whereupon the shuttle table will beadvanced over the previously-deposited cartons with the partially openflaps. When the shuttle table reaches its furthest forward position thecircuit for moving the restraining bar into operative position will alsoenergize a timer that will lower the cross-frame enough for theunderside of the table to press down on the partially-open flaps of thecartons beneath and substantially close them. Then the shuttle table isretracted to deposit the next layer of cartons.

A difficulty with this arrangement is that the electric eye systemmerely senses when it rises above the cartons already on the pallet, butcannot sense whether the flaps are open a little or a lot and the timerlowers the frame a fixed period of time which may result in morepressure being applied than is wanted and the retracting movement of theshuttle table from which its load has not been discharged may drag onthe top layer of cartons already in place and even disturb the entireload.

In FIGS. 21 to 24 there is disclosed a means for avoiding thisobjection. Assuming that the control box and limit switches are on thevertical frame column 25, this modification discloses a bar 270extending up along one side of the other column 26. It is supported onat least two brackets 271 and extends from a distance slightly above thehome level .to near the top of the frame. The brackets 271 have slotstherein with set screws 272 for securing the bar to the brackets in suchmanner that the bar may be adjusted vertically relatively to thebrackets.

The bar 270 has holes 273 therein at regular intervals, preferably aboutan inch from center to center. Pins or pegs 274 are removably set inthese holes at regularly-spaced distances. If the cartons with the flapsfolded down are about 12 inches in thickness, these pins, 274, willnormally be on 12-inch centers, but if the cartons are thicker, theywill be placed further apart, and for thinner cartons closer together.

On the underside of the transverse frame, as for example on the bottomflange of one of the side frame sections 40 there is a flag switch 275that will ride past the pins or pegs 274 when the cross-frame is movingup, but will be operated by contact with the first peg it encounters onthe way down to stop the travel of the cross-frame.

The sequence may be followed by reference to the block diagram in FIG.4. Current supplied through line 276 and the ground drives motor 30upwardly as long as no light flows between elements such as 136-136a(FIG. 13) and electric eye control unit 136k. When light passes betweenthe elements 136-136a, indicating that the elements have been raisedabove the stack on the pallet with the last layer having upturned flaps,motor 30, which is raising the frame will be stopped. At the same timecurrent will flow through line 277 to drive shuttle table motor 71 inthe forward direction. When the shuttle table has been driven forward tothe extended position, switch will open to stop motor 71 and currentwill flow through line 278 and timer 279 to flag switch 275 to thereverse lead of motor 30. This will start lowering the cross-frame. Wheneither flag switch 275 is opened by contact with a peg 274, or the timeropens the circuit, the operation of motor 30 will down, in whichposition it closes a circuit through line 169 to manual up switch 114which is in series with normally closed upper limit switch 125 and relayswitch 114a. One terminal of switch 114a connects through line 114b withthe up terminal of reversing switch a.

When manual up switch 114 is closed, it first energizes magnetic switch1140 to close this switch, whereupon the motor 30 will be operated toraise the crossframe as long as the manual switch is held closed, but ifthe frame should by chance go too close to the top of the upright, limitswitch 125 would open the circuit and close it only if the cross-framestarted to lower.

There is a branch line 170 from line 169 that leads to one terminal ofmanual down switch, which is in series with normally closed bottom limitswitch 122 and relay or magnetic switch 115a, the second terminal ofwhich leads up through line 1l5b to the down terminal of reversingswitch 30a. When the manual down switch 115 is closed, switch coil 1 150will first be energized to close switch 115a and the cross frame motor30 will then be energized to lower the frame. If the cross-frame startsdown or is below the home position, limit switch 122 will be operated toopen the circuit if the cross-frame should be lowered below its normaloperating range. When the cross-frame travels down from its up positionabove the home switch 120 or up from below that switch, it willmomentarily open switch 120 even if switch 114 or 115 is held closed,breaking the circuit through coil 1 14c of switch 114a or coil 1150 ofswitch 115a to stop the travel of the cross-frame at this level. Flagswitches 121 and 122 are shunted around switch 120 to be operated afterthe vertical frame moves up or down past home position both forautomatic operation and to prevent a condition that would arise if theswitch 120 should be in an off position due to slight overtravel.

Line 164 also leads to one terminal of switch 112 which is the manualswitch for operating motor 71 to propel the shuttle table to the leftfrom its retracted position, so that when the switch is pushed closed, acircuit will be completed through this switch to line 112a and normallyclosed limit switch 130 to line 130a to operate motor 71 until theshuttle table at its forward limit of travel opens limit switch 130 tostop it. When manual switch 113 is closed, a circuit will be completedthrough line 113a to normally closed limit switch 127 to line 127a tooperate the motor 71 in the reverse direction to retract the shuttletable until limit switch 127 is opened by the shuttle table reaching itsfully retracted position.

As before mentioned, there may be two safety switches 131 and 131a onthe forward end of the shuttle table 131 to be actuated if the shuttletable should inadvertently be moved forward when the cross-frame was nothigh enough for the shuttle table to clear the load. This switch isschematically indicated in the diagram in line 130a. It is normallyclosed, but upon the forward edge of the shuttle striking apreviouslypositioned load on the pallet, it will open line 130a and stopthe motor 71. Switch 131a on the under surface of the shuttle isarranged to contact the top of the load, should the table andcross-frame be inadvertently or accidentally lowered onto the load onthe pallet. It is connected from line 164 to the emergency off relay117a in parallel with emergency off switch so that operation of eitherswitch 131a or 117 to closed position will open the circuits thatcontrol both motors.

The fundamentals of a circuit for manual or semiautomatic operation ofthe machine have been here indicated for completeness of disclosure. Toautomate these circuits to perform in the manner hereinbefore describedwith electric eyes to control up and down travel and switches to raisethe crossframe clear of the load on the pallet after the last layer hasbeen deposited, involves only conventional relay circuits which form nopart of this invention, and which have therefore not been shown ordescribed, except some elements have been included to indicate thecapability of so adapting the machine to a system where, after theoperator has placed a layer of articles on the table, the pushing of onebutton will complete the full cycle of bringing the cross-frame to theproper level, depositing the articles on the pallet and returning thecross-frame to the home position.

As shown in FIG. 10, limit switch 125 is vertically adjustable, which isdesirable for automatic operation, but for manual operation it may befixed, or duplicated as at 125a in FIG. 9.

While the apparatus as above described has been successfully used incommercial applications, the restraining bar 80 in its lower oroperating position is at the end of lever arm 79 on the sleeve 78,which, as explained above, is operated by fluid pressure cylinder 83,piston rod 82 and crank arm 81. The thrust against the bar,

particularly with heavier crates or cartons is exerted therefore throughan unfavorable leverage, requiring high pressure in the cylinder 83 tohold the bar steady when the shuttle table is retracting and the load isbeing pushed off. Any slight yield that allows the restraining bar todelay in starting the discharge of a load onto the pallet results in thelayer being improperly positioned.

In the modification shown in FIGS. 17 to 20 inclusive there is anarrangement wherein the restraining bar is on dead center with the axisabout which it pivots when it is in load-restraining or obstructingposition so that the thrust is exerted in the direction of the length ofthe lever on which it is carried and resisted in the studs about whichthe arms rotate so that only moderate pressure is required in theoperating cylinders for moving the restraining bar into and out ofload-obstructing position. Also the levers on which the bar is carriedare articulated intermediate their ends in such manner that the bar isthrust forward in the direction of the load to a slight extent as itmoves into operative position and retracts as it lifts from suchposition.

In FIGS. 17 to 20 I have shown the mechanism at one side only of themachine and it is duplicated on the other side. The side plate 44corresponds to side plate 44 of FIG. 5, and 26 is one of the uprightcolumns. There is a structural section extending across the machineconnecting the tops of the side plates 44, as in the structurepreviously described.

The plate 44 has two vertical rows of equally spaced holes therethroughat 247 and a mounting block 248 is secured to the inner face of theplate 44 by bolts (not shown) passing through the mounting block andside plate 44 and fixed with nuts (not shown). This enables the mountingblock to be fixed at selected levels, so that its position is adjustedto the load being handled. The mounting block has a fixed stud shaft248a projecting therefrom toward the center of the table. On the

1. Apparatus for stacking articles on pallets which comprises: a. a basestructure with a pair of spaced parallel upright columns thereon andhaving a pallet support at one side of the columns on which a pallet isplaced for loading, b. an elongate frame supported between its ends formovement upwardly and downwardly on said columns, the elongate framehaving a loading end and an unloading end at opposite sides of saidcolumns, the unloading end being positioned over said pallet support,the elongate frame having side frame members spaced to clear the twoopposite sides of a load being stacked on a pallet placed on saidsupport, and cross members connecting the side frame members and spacedto clear the other two sides of the load being so stacked, the sideframe members and cross frame members defining an opening at theunloading end of the cross frame so arranged that the side members andcross members may surround the uppermost portion of a stack beingarranged on a pallet, the pallet support being centered under saidopening, c. a load-transferring shuttle table above and supported onsaid elongate frame and movable back and forth over the elongate framebetween a retracted load-receiving position at the loading end of saidframe and an extended position over the unloading end of said frame, d.a load-restraining means supported on the elongate frame intermediateits ends movable between a raised position over said elongate framewhere it is clear of any load being carried on the shuttle table fromthe receiving end of the elongate frame toward its extended position anda lowered position where it restrains movement of a load on the shuttletable when said shuttle table is moved from the extended position oversaid elongate frame to the retracted position, e. means for controllablyraising and lowering the elongate horizontal frame, f. means forcontrollably moving the shuttle table back and forth on said elongateframe, g. means for controllably moving the restraining means betweenits raised position and its lowered position, and h. stack-supportingmeans on the frame movable in the area of said opening to engage theuppermost portion of the stack being formed on the pallet and brace itwhen the shuttle table is moving from its extended position back fromthe unloading end of the frame toward the loading end.
 2. Apparatus forstacking articles on pallets as defined in claim 1 wherein the saidopening at the unloading end of the elongate frame at its lowermostlimit of travel on said columns is arranged to surround a pallet whichis placed on said pallet support and the shuttle table is then at alevel where it may move over and clear the top of a pallet sopositioned, said means for controlling the raising and lowering of theelongate frame comprising: a. a reversible electric motor and meansdriven thereby for raising and lowering the elongate frame, b. a flagswitch arranged to stop said motor whether the frame is moving up ordown at a home position intermediate the lowermost and uppermost limitsof travel of the frame at a level convenient for arranging a load on theshuttle table, and c. control switches for selectively moving theelongate frame downwardly or upwardly from said home position. 3.Apparatus for loading articles on pallets as defined in claim 1 whereinsaid stack-supporting means on the frame movable in the area of theopening is a load-engaging member reciprocable in the direction of thelength of the elongate frame at a level to engage the uppermost tier ofarticles on the stack across substantially the entire width of thestack, and means for moving said member toward the stack when theshuttle table is about to place additional articles on the stack andretract it after said additional articles have been placed on the stack.4. Apparatus for loading articles on pallets as defined in claim 3 inwhich there is a second such supporting member on the elongate frameopposite the first in a position to move into and out of position toconfine the articles on the top tier at the side of the load oppositethe side which is contacted by said first member, and means for movingthe second member into and out of article-engaging positionsimultaneously with the first.
 5. Apparatus for loading articles onpallets as defined in claim 4 in which fluid pressure cylinders operatesaid two members in unison.
 6. Apparatus for loading articles on palletsas defined in claim 4 in which there are two other such supportingmembers on the elongate frame for engaging the said top tier of articleson the two sides at right angles to said first two members and similarlymovable toward and away from the top tier but at right angles to thedirection of movement of said first and second support members. 7.Apparatus for stacking articles on pallets which comprises: a. a basestructure with a pair of spaced parallel upright columns thereon, b. anelongate frame supported between its ends for movement upwardly anddownwardly on said columns, one end of the elongate frame at one side ofthe columns being a loading end and the other end at the other side ofthe columns is an unloading end, c. a load-transferring shuttle tableabove and supported on said elongate frame and movable back and forthover the elongate frame between a retracted load-receiving position atthe loading end of said frame and an extended position over theunloading end of said frame, d. a load-restraining means supported onthe elongate frame intermediate its ends movable between a raisedposition over said elongate frame where it is clear of any load beingcarried on the shuttle table from the loading end of the elongate frametoward its extended position at the unloading end and a lowered positionwhere it restrains movement of a load on the shuttle table when saidshuttle table is moved in the reverse direction, e. means forcontrollably raising and lowering the elongate horizontal frame, f.means for controllably moving the shuttle table back and forth on saidelongate frame, g. means for controllably moving the restraining meansbetween its raised position and its lowered position, h. the uprightcolumns being structural sections having a web with confronting spacedparallel flanges, said elongate frame having an upwardly-extending sideplate at each side thereof along the outer face of which is mounted avertical series of at least three rollers spaced one above another andadjustable horizontally with respect to one another, the rollers beingso arranged that the upper and lower ones roll against one of said sideflanges of a column and the intermediate one rolls against the otherside flange whereby the elongate frame is held against tipping in eitherdirection from a horizontal position but is easily movable up and downalong said columns, i. the sideplates having chains attached theretothrough which raising and lowering thereof is effected, wherein saidrestraining means comprises two levers, each one pivotally mounted onone end to one said side plates, a restraining bar connecting the freeends of said levers, the levers being movable in a vertical arc from aposition above the plane of movement of the shuttle table downwardly toa level where the restraining bar will contact articles on the shuttletable to restrain them from movement with the shuttle table, thearrangement being such that the restraining bar is on a horizontal deadcenter with the pivotal mountings of said levers on their respectiveside plates when the bar is in load-restraining position, there being afluid pressure cylinder and piston on each said side plate for movingthe respective levers simultaneously, said cylinders and pistons beingarranged with respect to said levers that the piston of each is fullyretracted into its cylinder when the restraining bar is inload-restraining position so that the piston cannot retract further whenpressure is exerted against the restraining bar.
 8. Apparatus forstacking articles on a pallet as defined in claim 7 wherein each of saidlevers is a toggle lever with first and second sections pivotally joinedto each other and with one end of the first section being pivotallymounted on the side plate, the ends of the second sections of the twotoggle levers being connected by a restraining bar extendingtransversely across the plane of travel of the shuttle table, saidtoggle levers each being straight from end to end when the restrainingbar is in load-restraining position and the pivotal mountings for therespective toggle levers and the pivotal joint between the first andsecond sections of each is on dead center, the second section of eachtoggle lever being free to swing in an arc downwardly relative to thefirst section through a limited arc less than 90* when the toggle leversare raised to move the restraining bar to its load-clearing position,and means for preventing said levers from swinging downwardly past saiddead center position.
 9. Apparatus for stacking articles on pallets asdefined in claim 8 in which the pivotal mounting for said levers arearranged to be adjustably fixed on the side plates to be raised andlowered to adjust the height of said levers and the restraining barrelative to the shuttle table, and means for correspondingly adjustingthe position of the respective fluid pressure cylinder and piston unitsas the pivotal mounting for the levers is adjusted.
 10. Apparatus forstacking articles on pallets as defined in claim 7 in which therestraining bar is adjustable lengthwise along said levers to vary theposition at which the restraining bars will be effective to beginremoval of a load from the shuttle table when said table retracts. 11.Apparatus for stacking articles on pallets which comprises: a. a basestructure with a pair of spaced parallel upright columns thereon, b. anelongate frame supported between its ends for movement upwardly anddownwardly on said columns, and having a loading end and an unloadingend, c. a load-transferring shuttle table above and supported on saidelongate frame and movable back and forth over the elongate framebetween a retracted load-receiving position at the loading end of saidframe and an extended position over the unloading end of said frame, d.a load-restraining means supported on the elongate frame intermediateits ends movable btween a raised position over said elongate frame whereit is clera of any load being carried on the shuttle table from thereceiving end of the elongate frame toward its extended position and alowered position where it restrains movement of a load on the shuttletable when said shuttle table is moved from the extended position oversaid elongate frame to the retracted position, e. means for controllablyraising and lowering the elongate horizontal frame, f. means forcontrollably moving the shuttle table back and forth on said elongateframe, g. means for controllably moving the restraining means betweenits raised position and its lowered position, and h. a reversiblefriction drive for moving the shuttle table back and forth over theelongate frAme and control circuits for effecting operation of saidreversible friction drive at any level of the elongate frame between thelowest and highest positions thereof.
 12. Apparatus for stackingarticles on pallets as defined in claim 11 wherein there is an electriceye system arranged to stop the upward travel of the elongate frame whensaid frame is above the home position and is at a level where theshuttle table may move from the retracted position to its extendedposition and just clear the uppermost layer of articles on the palletbeing loaded.
 13. Apparatus for stacking articles such as cartons withpartially-open flaps on pallets as defined in claim 12 wherein saidelectric eye system after stopping the upward travel of the elongateframe comprises means for effecting the operation of said friction driveto move the shuttle table to its extended position and means to effectlimited downward travel of the elongate cross-frame with the shuttletable in such position, means for selectively positioning pegs at spacedintervals along the side of one of said upright columns, and means onsaid elongate frame arranged to engage one of said pegs when theelongate frame is then moving down to stop such downward travel when thepartially-open flaps of the cartons of the last deposited layer havebeen closed by contact with the underside of said shuttle table in itsextended position as the frame is lowered.
 14. Apparatus for loadingarticles on pallets one layer at a time as defined in claim 11 whereinsaid means for controllably moving the shuttle table back and forth overthe elongate frame comprises a friction wheel on the elongate framebearing against the underside of the shuttle table and a reversibleelectric motor for driving said friction wheel.
 15. Apparatus forloading articles on pallets as defined in claim 14 wherein the frictionwheel is resiliently urged against the underside of the shuttle table.16. Pallet loading apparatus and the like comprising: a. a verticalframe with spaced upright columns, b. an elongated cross-frame betweenthe upright columns and supported for up-and-down movement in thecolumns, c. the cross-frame comprising parallel spaced beams and havinga rear end portion and a forward end portion, the space between thebeams at the forward end portion providing an open area, the beams ateach side of the frame having rollers at spaced intervals therealong, d.a shuttle table suported on said rollers for back and forth movementalong the cross-frame on said rollers between a retracted position overthe rear end of the cross-frame to an extended position over said openarea at the forward end of the cross-frame, e. a restraining barsupported on the cross-frame intermediate the forward and rear endportions movable between an elevated position above the shuttle table toa load-obstructing position close to the top surface of the shuttletable, f. means for raising and lowering the cross-frame, g. means formoving the shuttle table between the retracted and extended positions,h. means for moving the restraining bar between the elevated andload-obstructing positions, i. a pallet-supporting means under the openspace between the beams at the forward end of the cross-frame on which apallet to be loaded may be removably centered, the open space betweensaid beams at the forward end of the transverse frame being longer andwider than a pallet which said pallet-supporting means is designed toreceive, whereby a load may be placed in successive layers on the palletso placed with the beams of the cross-frame being below the top of apreviously-deposited layer, and j. a friction drive for effectingback-and-forth movement of the shuttle table.
 17. Pallet loadingapparatus as defined in claim 16 wherein there is a support resilientlysuspended from the cross-frame at a location beneath the forward end ofthe shuttle table when it is in retracted position and under the rearportion Of the shuttle table when it is in its extended position, atleast one friction wheel mounted on said support with its peripheryresiliently urged against the under surface of the supporting table, anda reversible motor for driving the friction wheel to provide thefriction drive for effecting the back-and-forth movement of the table.18. Pallet loading apparatus as defined in claim 16 wherein said palletsupport comprises a roller table which in turn comprises parallel rollerconveyor sections and a supporting frame to which said sections areaffixed, said supporting frame being removably set in the base and ofsuch dimension that the conveyors may be selectively set crosswise orlengthwise with respect to the longitudinal axis of thevertically-movable cross-frame.
 19. Pallet loading apparatus as definedin claim 16 in which said friction drive is a motor-driven frictionwheel on the cross-frame resiliently bearing against the underside ofthe shuttle table, the shuttle table being free to lift verticallyshould the shuttle table strike the top of a load by accidental loweringof the cross-frame when the shuttle table is over the open forward endof the cross-frame and it strikes the load in position on the pallet.20. Pallet loading apparatus as defined in claim 17 wherein there areswitch means on the forward end of the shuttle car to stop its drivingmeans if the shuttle table moves forward against the load being placedon a pallet and also for stopping the means for lowering the cross-frameif the cross-frame lowers to bring the shuttle table into contact with aload already in position on the pallet.